The conventional arrangements of transformable toys, of which figures are transformed from a vehicle or an animal into a doll robot, are disclosed in the Japanese Laid-Open Patent Publication (Kokai) No. 10442/1997 or the Japanese Laid-Open Patent Publication (Kokai) No. 28933/1997. Various kinds of transformable toys are commercially available on the market. In the conventional transformable toys, various kinds of joint structures are used to change the figures thereof.